The present invention relates to apparatus for and a method of extracting samples of liquid product from a vessel, and in particular to apparatus for and a method of extracting samples of wine from wine holding tanks.
Wine is produced by fermenting grape juice or grape must which contains not only the juice, but also the seeds and skins of the grapes. When the grape sugar is fully consumed, fermentation is complete and wine is produced. While the basic elements of wine production are relatively simple, the manipulation of grapes, juice, must and wine in manners to yield desired flavors and aromas is difficult. Wine makers try to produce specific desirable aromas and flavors in wine, while at the same time minimizing those that are undesirable. It is also necessary that the wine acids and alcohol be controlled, since if wine is too acidic it may taste sour, while if its ethanol level is too high it will have a strong taste of alcohol. An important factor that contributes to a wine's character is the type of grapes used, which influence a wine's flavor, alcohol content, acidity and color. Red and white wine production is generally the same, except that in making white wine the juice from white grapes is separated from the skins prior to fermentation, while in making red wine red grapes are used and fermentation takes place in the presence of the grape skins, so that red pigments and other compounds in the skins are extracted during fermentation to impart a red color to the wine as well as other features. Red grapes may be fermented without the skins, in which case the limited amount off pigment released when the grapes are crushed yields a blush or rose wine that is light in color.
In producing wine, grapes harvested from a vineyard are mechanically crushed to separate the stems from the grapes and to crack open the grapes to release the juice. To make white wine, the must yielded by the crushing process is pressed to separate the juice from the skins, with the amount of pressure applied influencing what flavor compounds are extracted from the skins. The white grape juice obtained by pressing is then introduced into a fermentation tank. In producing red, the must from the crusher, which includes both the juice and skins, is transferred to a fermentation tank. The fermentation tanks are usually made of stainless steel or wood, with the material used and the temperature of fermentation influencing the character of the wine. A number of the aroma components of wine are volatile and leave the wine by evaporation, and as evaporation occurs faster at higher temperatures, to retain aroma characters in the wine, the temperature of fermentation is controlled, usually by direct cooling of the fermentation tanks.
Fermentation may be allowed to proceed by relying only on the yeast naturally present on the grape skins and in the wine making equipment, or yeast may be added to the must in a process known as inoculation, with the particular species of yeast used resulting in the presence of particular positive and negative aroma characters in wine. Yeast under stress produces hydrogen sulfide, and to avoid this undesirable quality rotten egg smell, nutrients may be added to the fermentation tank. Also influencing wine character are the duration of fermentation and naturally occurring microorganisms that may grow in the must or juice and affect the flavors and aromas of the wine. For example, lactic acid bacteria consume acids and reduce the wine's acidity, and also produce other aromas including the buttery smells found in wine. Steps may therefore be taken to restrict the growth of lactic acid bacteria, especially if the wine is already low in acidity or if the buttery smell would dash with other aromas of the wine. Another type of bacteria, acetobacter, can spoil the wine by converting alcohol to vinegar.
Wine appears cloudy after fermentation is complete, and the yeast and other solids in the wine are therefore allowed to settle to the bottom of the tank, forming sediment called the lees. The dear wine resulting from settling is then racked or drawn off the lees and stored in a clean cask. In a process called fining, the wine may be further clarified by adding ingredients that attract unwanted particles such as proteins that cause cloudiness and which then settle to the bottom of the cask for collection and removal.
Following fermentation and clarification the wine is aged. The manner in which wine is aged affects the flavors and aromas present in the finished wine. For example, wine aged in oak barrels picks up flavor and aroma characters from the oak, a desirable quality in some wines. Wine may also be aged under conditions which encourage loss of some of the volatile fruity compounds, so that the wine is then richer in other characters. Exposure to air during aging causes phenolic wine compounds to combine with each other and produce tannins that over time become large and form reddishbrown sediment in the bottle, reducing wine bitterness and astringency. The time for which wine is aged before bottling determines the extent to which these reactions occur, and even after bottling the wine may continue to slowly age for many years.
Because of the many different variables involved in the production of wine and the large number of different qualities that may be imparted to wine, it is essential that the wine be sampled at various stages of its production process in order that the characteristics it is developing might be detected and timely controlled to yield wine having specifically desired qualities. Prior to commencement of fermentation, the top of the fermentation tank is open and samples of the must mixture are readily available. Once fermentation begins, the tank is closed to prevent contamination of its contents, for example by airborne bacteria and molds, and the art contemplates that further samples then be obtained by withdrawal through a hose connection made through a bung opening located near the bottom of the tank and controlled by an inline ball valve. A problem with this sampling technique is that as the must ferments to produce wine and when the wine is subsequently allowed to clarify and age the lees, consisting of dead yeast cells and other solids, forms as a several inch thick sediment layer on the bottom and lower side walls of the tank in the region of the bung opening. As a result, wine samples withdrawn from the tank through the bung opening are contaminated by sediment, which can also enter and dog the hose and ball valve.